Electrodynamic transducer

ABSTRACT

An input/output assembly comprises a pair of members coupled such that a first thereof carrying an input/output element is reciprocative relative the second at each position of the second; and both members are translocatable simultaneously in a path extending transversely of the direction of reciprocation. First and second electrical induction coils, having portions which are coupled in the magnetic flux field of a permanent magnet structure, are secured to the first and second members, respectively, with the coupled portions disposed in planes having orthogonal aspects, each to the other. The second coil is circumposed about a rail which is included in the magnetic structure and is movable longitudinally thereof in response to magnetmotive forces when the transducer is adapted as a motor and in response to mechanical forces applied to the element when the transducer is adapted as a generator for generating an electrical effect therein. The displacement of the second coil results in simultaneous movement of the first coil longitudinally of said rail. The first coil is arranged in said flux field for movement transversely of said rail independently from the second coil such that the element is reciprocated when the transducer operates as a motor and an electrical effect is generated therein upon movement of the element along a vector having a velocity coordinate corresponding to the first coil when the transducer operates as a generator. The rail may be arcuate whereby the first member is reciprocative radially, along an r axis, independently of said second member with which it is simultaneously translocatable angularly, along a theta axis in a plane with the r axis.

United States Patent Cless et al.

[54] ELECTRQDYNAMIC TRANSDUCER [72] Inventors: Gerhard Cless, Skokie;Jerome L. De Boo,

Barn'ngton, both'of lll.

[73] Assignee: Teletype Corporation, Skokie, lll.

[22] Filed: May 28, 1970 [2l] Appl.No.: 41,486

[52] U.S.Cl ..346/29,178/l8,3l0/27,

318/35, 336/121, 340 /l95, 346/139 R [51] Int. Cl. ..G0ld 5/20 ISSIField of Search..; ..346/29, 139 R; 318/35, 575,

318/686, 687, 135,195, 38; 178/18-20, 43; 340/195, 5 R, 3lO/l2-l4, 27',336/l 19-123, 125, 33/1 C, 1 PT, 1 CC Kom et al ..343/5 R X PrimaryExaminer-Joseph W. Hartary Attomey-J. L. Landis and R. P. Miller 51 Feb.8, 1972 [57] ABSTRACT An input/output assembly comprises a pair ofmembers coupled such that a first thereof carrying an input/outputelement is reciprocative relative the second at each position of thesecond; and both members are translocatable simultaneously in a pathextending transversely of the direction of reciprocation. First andsecond electrical induction coils, having portions which are coupled inthe magnetic flux field of a permanent magnet structure, are secured tothe first and second members, respectively, with the coupled portionsdisposed in planes having orthogonal aspects, each to the other. Thesecond coil is circumposed about a rail which is included in themagnetic structure and is movable longitudinally thereof in response tomagnetmotive forces when the transducer is adapted as a motor and inresponse to mechanical forces applied to the element when the transduceris adapted as a generator for generating an electrical effect therein.The displacement of the second coil results in simultaneous movement ofthe first coil longitudinally of said rail. The first coil is arrangedin said flux field for movement transversely of said rail independentlyfrom the second coil such that the element is reciprocated when thetransducer operates as a motor and an electrical efi'ect is generatedtherein upon movement of the element along a vector having a velocitycoordinate corresponding to the first coil when the transducer operatesas a generator.

The rail may be arcuate whereby the first member is reciprocativeradially, along an r axis, independently of said second member withwhich it is simultaneously translocatable angularly, along a 6 axis in aplane with the r axis.

10 Claims, 7 Drawing Figures PATENTEBFEB 8 m2 SHEET 1 OF 2 INVENTORSGERHARD CLESS JEROME L. DEBOO ATTORNEY ELECTRODYNAMIC TRANSDUCER FIELDOF THE INVENTION The present invention relates to transducers.Particularly it relates to an electrodynamic transducer.

BACKGROUND OF THE INVENTION A transducer of the indicated class isuseful as a motor in a positioning device or a plural axis plotter,because of its rapidity of responsiveness to mechanical input forces andthe high level of resolution which it'enables to achieve. A pair ofcontemporaneously filed applications of Gerhard Cless, (an inventorherein) and Allan G. Wallskog and which are assigned to assignee of thepresent application and are identified further as follows: (1) Ser. No.41 ,485, titled PRINTING AS- SEMBLIES AND METHODS, and (2) Ser. No.41,335, titled PRINTER TYPE CARRIER ASSEMBLY, describe and claimtransducers of the indicated class and disclose embodiments of suchtransducers as positioning devices in teleprinters.

Moreover, such construction could be adapted as a generator forproducing plural electrical outputs each corresponding to the velocityrelative an axial component of a vector along which an input member ismoved.

It is an object of the present invention to provide a novel transducer.

It is another object of the invention that the transducer beelectrodynamic.

It is an additional object of the invention to move a body along anyvector having plural axial components, particularly in response toplural input forces corresponding to said axial components.

It is a still further object of the invention to provide a novel motor.

It is a yet further object of the invention to provide a plural axesplotter.

Further, it is an object of the invention to provide a novel generator.

Moreover, it is an object of the invention to produce a plurality ofoutputs corresponding to the velocity relative axial coordinates of amovement vector of an input member.

- SUMMARY OF THE INVENTION The foregoing and other objects of theinvention are effected according to one aspect of the invention by atransducer comprised of an assembly arranged for relative andsimultaneous movement in transversely extending paths, andelectrodynamic means and mechanical means associated in input-outputrelationship with said assembly for translating power in one form topower in another.

From another aspect, the objects of the invention are effected byproviding, as electrodynamic means, a rail defining a magnetic circuitand a pair of electrical inductance coils coupled in the flux field ofsaid magnetic circuit. Each coil is connected to one of a pair ofmechanically coupled members comprising the assembly. One of said coilsis disposed about said rail for movement longitudinally thereof to moveboth members along one axis; and one of said members is reciprocativerelative the other thereof.

By adapting an input/output element which is carried from thereciprocative member as an inscriber, the transducer is adapted as adual axes plotter. By adapting said element for input, a pair of outputswill be generated in said coils corresponding to the velocity relativethe coordinate axes of a vector along which the input element is moving.

BRIEF DESCRIPTION OF THE DRAWINGS In the ensuing detailed description ofthe invention, reference ishad to the accompanying drawings in which:

FIG. 1 is an elevational view of a dual axes plotter embodying theinvention, a center shaft shown in section, and a fragment of anassociated record carrier shown in phantom;

FIG. 2 is a view according to section line 22 of FIG. I;

FIG. 3 is a detailed view according to the line 3-3 of FIG. 1, a hangerhaving been omitted;

FIG. 4 is a view similar to FIG. I, however, showing a motor embodying amodified form of the invention;

FIG. 5 is a view according to line 5-5 on FIG. 4;

FIG. 6 is a view according to line 6-6 on FIG. 5; and

FIG. 7 is a wiring scheme adapted for controlling the modified form.

DETAILED DESCRIPTION OF THE INVENTION member is carried from the secondmember which is also mounted for movement in a lineal path, buttransversely of the direction of reciprocation.

Coupling means for simultaneously moving first and second members 12 and14 and enabling relative movement thereof comprises a plurality ofroller-type bearings 16 which are secured from the second member toprovide a straight track 18 (FIG. 1). An elongated body portion 20 offirst member 12 is engaged in track 18 for reciprocating said firstmember relative second member 14.

A rail 22 defines a lineal path which second member 14 is movablelongitudinally. To effect such movement, an electrical inductance coil24 is wound in a plane perpendicular to and is circumposed about saidrail and has a section 26 (FIGS. 2 and 5) which is rigidly secured to aproximate part of second member 14. The coil is supported for movementlongitudinally of said rail whereby the second member and the coil movetogether, and as will be apparent from ensuing description, in responseto an electrical effect through said coil when the transducer is adaptedas a motor.

In the illustrated embodiment, rail 22 is arcuate being concentric withand disposed about an axis defined by a shaft 28. The latter comprisesmeans for supporting transducer 10 such that the aspect of track 18 isradial to said shaft and orthogonal to the path along which secondmember 14 is displaceable. To provide the support, the second member hasa central extension 30 with a bearing-lined aperture 32 enabling angularmovement of the second member about shaft 28.

Rail 22 is a pole piece, being fabricated from soft iron or the like. Itis of low magnetic reluctance and low magnetic retentivity in apermanent magnet assembly or structure generally designated 34 andcomprising electrodynamic means. Also included in the magnetic assemblyis a permanent magnet 36 having an arcuate configuration concentric withshaft 28. The permanent magnet is polarized through its thickness withopposed North and South poles (conventionally designed N and S in FIGS.2 and 3) being disposed on opposed parallel flat faces 38 and 40thereof. Polar face 40 is also spaced from a thereto parallel fiat face42 of rail 22, the spacing therebetween forming an airgap 43 to themagnetic flux in which one section 44 of coil 24 is magneticallycoupled. A pole piece 45 similar in fabrication and configuration torail 22 and concentric with shaft 28 has a flat face 46 which issuitably rigidly secured, by a suitable cementing or the like, to face38 of the permanent magnet.

A preferably nonmagnetic housing or hanger 47 (FIG. 2) comprises a flatplate 48 which is disposed parallel to pole piece 45. It has a centralbox 50 in which one end of shaft 28 is supported. In the embodiment ofthe invention of FIG. 2, the shaft is immobilized relative the hanger,but this feature is not critical to the invention. Peripheral flangemeans 52 integral with plate 48 is rigidly secured to the periphery ofmagnet 36 whereby magnet structure 34 is hung or supported from shaft28.

In each illustrated embodiment pole piece 22 has a pair of opposite ends54 and 56 (FIG. 3) and pole piece 45 has a pair of opposite ends 58 and60. Ends 54 and 58 are aligned at one end portion of magnet structure 34and are magnetically interconnected by soft iron piece 62. Ends 56 and60 are aligned at the other end portion of the magnet structure and aremagnetically interconnected by a soft iron piece 64. Thereby, pieces 62and 64 are spaced apart ends of the magnet structure and complete anelongated physical loop and a magnetic circuit defining therewithin airgap 43. In this loop, rail 22 and pole piece 45 are elongated parallelsections of opposite polarity. Permanent magnet 36 is disposed insidethe loop. Members 12 and 14 are disposed outside the loop.

An-electrical inductance coil 66 is included in the electrodynamic meansand has a nnagrnetically coupled portion 67 which cuts the magneticlines of flux in airgap 43 for reciprocation in a path extendingnormally to the path of movement of coil 24. The coupled portion isslightly spaced from section 44 of coil 24 and defines a plane which isorthogonal to a plane defined by coil 24. A rigid linkage designated 68comprises a pair of spaced-apart arms 70 from which coil 66 is rigidlysupported in the airgap. A connecting component 72 integral with arms 70is rigidly connected to first member 12 for reciprocating saidlast-mentioned member in response to an electrical efi'ect through coil66 when the transducer is adapted as a motor.

The arrangement and disposition of coils 24 and 66 is such that magneticlines of flux flowing in the magnetic circuit defined by magneticconstruction 34 are effectively cut at right angles most efficiently tomove the members 12 and 14 in response to current flow in the coils whenthe transducer is adapted asa motor. In this connection, it is observedthat when current flows in one direction through any coil, movement ofan associated of members 12 and 14 will result in a correspondingdirection, whereas, current flow in an opposite direction in such coilwill result in movement of such member in an opposite direction.Accordingly, each time coil 24 moves magnetomotively, members 12 and14-will move simultaneously, whereas, only member 12 is responsive tomagnetomo tive reciprocation of coil 66. Furthermore, the arrangement ofparts in the illustrated embodiments is such that reciprocative movementis radial i.e., along an r axis of a two-axis system, whereas movementof member 14 is concentric to shaft 28, i.e., along a 6 axis ofsuchtwo-axis system.

To prevent interference of shaft 28 with the radial movement in theembodiment of FIG. 1, first member 12 has a central extension 74comprised of a pair of tines 76. They are disposed on opposite sides ofsaid shaft 28 and are engaged for reciprocation in an annular gooveformed between an annular shaft shoulder 78 and a retainer 80 suitablyheld on the reduced end portion of the shaft.

First member 12 has an outer end portion 81 in which is secured anelement 82. The latter is an input component when the transducer isadapted as a generator. It is an output component when the transducer isadapted as a motor.

Herein, the transducer is shown as a motor, particularly a dual (r-0)axes plotter; and element 82 is an inscriber. It is adapted to apply atrace 83 longitudinally of an arcuately disposed carrier 84 about theaxis of shaft 28 and according to the current through coils 24 and 66.

It is observed that in some aspects the invention herein embodied is notlimited to the arcuate configuration of rail 22. That is to say, saidrail could be straightened with attendant modification in the supportmeans for second member 14 to enable tracking of such straightened rail.Thereby, an illus- -trated device could be converted to an X-Y plotterin which the output element would then be movable along a vector havingstraight normal planar coordinates.

In the embodiment of the invention shown in FIGS. 4 and 5,

' transducer 10 incorporates feedback means as part of a servo circuit85 (FIG. 7) for controlling element 82. In said modified embodimentshaft 28 is joumaled for rotation in box 50 and, second member 14 isrigidly secured to the shaft.

Thereby upon translocation of coil 24 longitudinally of rail 22, theshaft will move angularly.

A pinion 86 is joumaled on shaft 28 distally from box 50. It is retainedfrom displacement axially of said shaft by bearing engagement withextension 30 of member 14 on one side thereof and with a retainer 88which bears against the pinion hub 90 on the other side thereof. Aninner extension 92 (FIG. 4) of first member 12 in this embodimentreplaces extension 74 of the first described embodiment and is fashionedas a gear rack. It is operatively meshed with the pinion, whereby, saidpinion has an angular condition corresponding to each radial position ofthe first member.

According to the exemplary scheme, selection of the position to which itis desired to move element 82 is effected electrically through aposition indicator 94 (FIG. 7). The output thereof is a composite signalwhich is impressed upon a position coordinate generator 96 through aconductive lead 98. There the input is divided into a pair of coordinatesignals which correspond to the positions to which it is desired todrive the coils 24 and 66, respectively, and such coordinate signals areprovided as inputs through a pair of conductors 100 and 102 to a pair ofservoarnplifiers 104 and 106 associated, respectively, with inductancecoils 66 and 24.

Displacement sensor means 108 for indicating each position of firstmember 12 in a radial path comprises a disc 110 which is mounted forrotation with pinion hub 90 and has a plurality of apertures (not shown)arranged annularly and radially according to a code such that an encodedcombination will occupy a fixed illuminating station for each angularcondition of pinion 86. A photosensor 112 is supported in a positionadjacent one face of the disc such that it will be impinged by rays oflight passed from a light source 114 through the apertures of disc 110occupying the' illuminating station. The light source is also fixed fromangular movement and arranged adjacent an opposed face of the disc andin consequence, for each angular position of the pinion, the sensor willbe encodedly excited correspondingly. i

A similar displacement sensor 116 comprises a light-encoding disc 1 18which is mounted parallel to disc 110 for rotation with shaft 28. It hasencoding apertures (not shown) and opposed faces adjacent which lightsource 114 and a fixed photosensor 120 are mounted in alignment suchthat a light code will be impressed on the last photosensorcorresponding to each condition of the shaft.

The signal generated by each photosensor will be transmitted through arespective one of leads 122 and 124 to a corresponding one ofservoamplifiers 104 and 106 as an input. There it will be algebraicallyadded, in a manner which is well known in the art with the inputreceived through an associated one of conductors 100 and 122 to producea resulting amplifier output signal to an associated one of inductancecoils 24 and 66 for driving element 82 from any given position to anyother selected position.

When transducer 10 is adapted as a generator, element 82 will be aninput component and inductance coils 24 and 66 become output elements.It is appreciated that then a voltage would generate in either or bothof the coils depending upon the velocity relative the axes of the vectoralong which element 82 is moving. For example, a mechanical input forceresulting in movement of element 82 only radially will generate anoutput effect only in inductance coil 66. On the other hand, if theinput force is a torque concentric with shaft 28, an induced voltagewill be generated only in the coil 24. However, when movement of element82 is along a vector comprised of both axial components, then a pair ofinduced effects will be generated in the coils as a function of thevelocity relative the coordinates of said vector. 1

As many modifications in the described construction could be conceived,and as many changes could be made therein without departing from thespirit and scope of the claims, it is intended that all matter containedin the accompanying specification shall be considered as illustrativeonly and not in a limiting sense.

We claim:

1. A transducer comprising:

a first member mounted for reciprocation;

a second member mounted for movement in a lineal path transversely ofthe direction of reciprocation;

coupling means for simultaneously moving said first and second membersin said lineal path;

an arcuate rail defining said lineal path, said second member associatedwith said arcuate rail for movement angularly about acenter;

a magnetic structure including said rail and defining an air gap with amagnetic flux field therein;

first and second electrical inductance coils rigidly connected to saidfirst and second members, respectively, and disposed in a pair of spacedapart planes in magnetically coupleable association in said air gap formovement with said first and second members; and I a writing componentcarried from said first member and translocatable in response toelectrical effects in said first and second inductance coils.

2. A transducer comprising:

a first member mounted for reciprocation;

a second member mounted for movement in a lineal path transversely ofthe direction of reciprocation;

coupling means for simultaneously moving said first and second membersin said lineal path;

an arcuate rail defining said lineal path, said second member associatedwith said arcuate rail for movement angularly about a center;

a pair of elongated magnet sections including said rail and of magneticmaterial, said sections defining an airgap therebetween;

a first inductance coil rigidly connected to said first member andarranged for reciprocation in said airgap in a direction transverse tosaid sections;

a second inductance coil rigidly connected to said second member andcircumposed about one of said sections for movement longitudinallythereof, and

an input element carried from said first member for generatingelectrical output effects in said first and second inductance coilsalong and jointly.

3. A transducer comprising:

a magnetic structure comprised of a rail and having an airgap with amagnetic flux field;

first and second inductance coils magnetically coupled and arranged formovement in said magnetic flux field along a pair of angularlyassociated axes of a two axes system, said second coil mounted aboutsaid rail and disposed in a plane extending transversely of said railfor movement along one of said axes, said first coil supported in aplane and spaced in said gap from said second coil for reciprocationrelative said second coil;

a shaft, said rail supported concentrically from said shaft, said secondmember having an extension mounted from said shaft for moving saidsecond coil along said rail in an arcuate path about said shaft;

means for changing the position of said coils simultaneously and alone,each relative to the other; and

an element connected to said changing means and arranged for movementalong any selected vector in said system to any selected position.

4. A transducer according to claim 3 characterized byrotational meansassociated with said shaft having an angular position associated witheach position of reciprocation of said first coil relative said secondcoil, and feedback means associated with said shaft and said rotationalmeans for generating signals corresponding to the positions of saidcoils.

5. A transducer according to claim 4 wherein said rotational meanscomprised a pinion mounted about said shaft, and a gear driveablyconnected to said first coil for rotating said pinion about said shaft.

6. A generator comprising:

a first input member,

a second input member; means for moving said input memberssimultaneously m one path and for reciprocating said first member onsaid second member in another path at any selected position in said onepath;

a first electrical inductance coil mechanically secured to said firstmember;

a second electrical inductance coil mechanically secured to said secondmember; and

a loop of magnetic material having opposed polar sections with anarcuate profile and defining therewithin a magnetic gap, the second coilcircumposed about one of said polar sections, the first coil movable inan arcuate path with said second coil and magnetically coupled on saidmagnetic gap for reciprocative movement independently thereof.

7. A generator according to claim 6 characterized by a permanent magnetsecured to the other of said polar sections for generating a flux fieldin said magnetic gap, and an input element connected to said members andarranged for movement directly to any position in a two axes system,said first and second coils being disposed in said gap in planes havingaspects, each normal to the other, whereupon movement of said elementalong a vector having a pair of axial components to any position aneffect will be generated in said coils.

8. A generator according to claim 7 wherein said coils are movable inintersecting paths corresponding to the pair of axes in said two axessystem, the effect generated in each coil being responsive to thevelocity relating to each axial component of a vector as said elementmoves to any position.

9. In an electrodynamic-mechanical transducer of the type having a pairof mechanical members coupled together for translocation simultaneouslyin a curvilinear path and for reciprocation of one member independentlyof the other member, and wherein translocation of both members is inassociation with one of a pair of inductance coils arranged for movementin a curvilinear path transversely of the path of movement of another ofsaid pair of coils associated with said reciprocation, the improvementcharacterized by:

a single magnetic flux field, both of said coils being disposed in saidsingle magnetic flux field for generating a pair of effects.

10. A combination according to claim 9 characterized by a pair ofconcentric members arranged for rotation in response to saidtranslocation and said reciprocation, and feedback means associated withsaid concentric members for providing intelligence as to theinstantaneous conditions of translocation and reciprocation.

1. A transducer comprising: a first member mounted for reciprocation; asecond member mounted for movement in a lineal path transversely of thedirection of reciprocation; coupling means for simultaneously movingsaid first and second members in said lineal path; an arcuate raildefining said lineal path, said second member associated with saidarcuate rail for movement angularly about a center; a magnetic structureincluding said rail and defining an air gap with a magnetic flux fieldtherein; first and second electrical inductance coils rigidly connectedto said first and second members, respectively, and disposed in a pairof spaced apart planes in magnetically coupleable association in saidair gap for movement with said first and second members; and a writingcomponent carried from said first member and translocatable in responseto electrical effects in said first and second inductance coils.
 2. Atransducer comprising: a first member mounted for reciprocation; asecond member mounted for movement in a lineal path transversely of thedirection of reciprocation; coupling means for simultaneously movingsaid first and second members in said lineal path; an arcuate raildefining said lineal path, said second member associated with saidarcuate rail for movement angularly about a center; a pair of elongatedmagnet sections includiNg said rail and of magnetic material, saidsections defining an airgap therebetween; a first inductance coilrigidly connected to said first member and arranged for reciprocation insaid airgap in a direction transverse to said sections; a secondinductance coil rigidly connected to said second member and circumposedabout one of said sections for movement longitudinally thereof, and aninput element carried from said first member for generating electricaloutput effects in said first and second inductance coils alone andjointly.
 3. A transducer comprising: a magnetic structure comprised of arail and having an airgap with a magnetic flux field; first and secondinductance coils magnetically coupled and arranged for movement in saidmagnetic flux field along a pair of angularly associated axes of a twoaxes system, said second coil mounted about said rail and disposed in aplane extending transversely of said rail for movement along one of saidaxes, said first coil supported in a plane and spaced in said gap fromsaid second coil for reciprocation relative said second coil; a shaft,said rail supported concentrically from said shaft, said second memberhaving an extension mounted from said shaft for moving said second coilalong said rail in an arcuate path about said shaft; means for changingthe position of said coils simultaneously and alone, each relative tothe other; and an element connected to said changing means and arrangedfor movement along any selected vector in said system to any selectedposition.
 4. A transducer according to claim 3 characterized byrotational means associated with said shaft having an angular positionassociated with each position of reciprocation of said first coilrelative said second coil, and feedback means associated with said shaftand said rotational means for generating signals corresponding to thepositions of said coils.
 5. A transducer according to claim 4 whereinsaid rotational means comprises a pinion mounted about said shaft, and agear driveably connected to said first coil for rotating said pinionabout said shaft.
 6. A generator comprising: a first input member; asecond input member; means for moving said input members simultaneouslyin one path and for reciprocating said first member on said secondmember in another path at any selected position in said one path; afirst electrical inductance coil mechanically secured to said firstmember; a second electrical inductance coil mechanically secured to saidsecond member; and a loop of magnetic material having opposed polarsections with an arcuate profile and defining therewithin a magneticgap, the second coil circumposed about one of said polar sections, thefirst coil movable in an arcuate path with said second coil andmagnetically coupled in said magnetic gap for reciprocative movementindependently thereof.
 7. A generator according to claim 6 characterizedby a permanent magnet secured to the other of said polar sections forgenerating a flux field in said magnetic gap, and an input elementconnected to said members and arranged for movement directly to anyposition in a two axes system, said first and second coils beingdisposed in said gap in planes having aspects, each normal to the other,whereupon movement of said element along a vector having a pair of axialcomponents to any position an effect will be generated in said coils. 8.A generator according to claim 7 wherein said coils are movable inintersecting paths corresponding to the pair of axes in said two axessystem, the effect generated in each coil being responsive to thevelocity relating to each axial component of a vector as said elementmoves to any position.
 9. In an electrodynamic-mechanical transducer ofthe type having a pair of mechanical members coupled together fortranslocation simultaneously in a curvilinear path and for reciprocationof one member independently of the other member, and whereintranslocation Of both members is in association with one of a pair ofinductance coils arranged for movement in a curvilinear pathtransversely of the path of movement of another of said pair of coilsassociated with said reciprocation, the improvement characterized by: asingle magnetic flux field, both of said coils being disposed in saidsingle magnetic flux field for generating a pair of effects.
 10. Acombination according to claim 9 characterized by a pair of concentricmembers arranged for rotation in response to said translocation and saidreciprocation, and feedback means associated with said concentricmembers for providing intelligence as to the instantaneous conditions oftranslocation and reciprocation.